Bun

Bun is a modern JavaScript runtime built from the ground up with three main goals: speed, elegant APIs, and a cohesive developer experience. It's designed to be a complete, all-in-one toolkit for your JavaScript and TypeScript projects, eliminating the need for separate tools.

It functions as a drop-in replacement for Node.js, natively implementing hundreds of Node.js and Web APIs like fs, path, and Buffer. This makes migration straightforward for most server-side JavaScript applications.

What sets it apart is its integrated nature and performance. It includes:

• A fast package manager that is fully npm-compatible.
• A built-in test runner that significantly outperforms alternatives like Jest.
• An integrated bundler and transpiler for your JS/TS code.
• A rich set of optimized, built-in APIs for common tasks.

By extending the high-performance JavaScriptCore engine with native code written in Zig, it achieves remarkable speed for running applications, installing packages, and executing tests. The ultimate aim is to reduce complexity and multiply developer productivity.